Image descriptionFollowing OsO4 intensification, DAB-positive areas (i.e., ductal epithelia) become distinctly bright. At higher magnifications, the morphology of cells and subcellular structures, such as the nucleus (→), can be clearly discernable.

Characteristic findings

When breast cancer tissue is stained with DAB alone, the morphology of the cells in DAB-positive areas remains indiscernible under a LVSEM. However, on OsO4 intensification, DAB-positive cells provide a strong contrast against the surrounding tissue, making it possible to clearly capture the details of their microstructure. At higher magnifications, LVSEMs also allow for the examination of the detailed morphology of these cells and their organelles (such as the nucleus).11)

Observations

Samples shown in Fig. 000006 (panels a and c) were stained with DAB alone, while those in panels b and d were treated with 2% OsO4 for one hour for color intensification after DAB staining. All samples were examined with a LVSEM. Color development with DAB alone fails to precisely delineate DAB-positive areas (Figs. 000006 a and c). However, OsO4 intensification enhances the contrast of these areas and provides well-defined images at higher magnifications.